Composite photographic printreceiving sheet



Sept. 29, 1953 w. J. M CUNE, JR

COMPOSITE PHOTOGRAPHIC PRINT-RECEIVING SHEET Filed NOV. 13, 1951 III III INVENTOR efiw/w Patented Sept. 29, 1953 COMPOSITE PHOTOGRAPHIC PRINT-RECEIVING SHEET William J. McCune, Jr., South Lincoln, Mass., assignorto Polaroid Corporation, Cambridge, Mass., a corporation of Delaware.

Application November 13, 1951, Serial No. 255,995 In Canada October 20,1948 6 Claims. (Cl. 95-88) vide a novel composite print-receiving sheetfor use in the performance of transfer processes, said sheet giving afinished framed print at the completion of the process.

Another object of the present invention is to provide a novel compositeprint-receiving sheet of the above type which includes, as part of thecomposite structure thereof, all of the reagents, including the liquid,for performing the transfer process.

These and other objects of the invention will in part be obvious andwill in part appear hereinafter.

The invention accordingly comprises the product possessing the features,properties and the relation of components which are exemplified in thefollowing detailed disclosure, and the scope of the application of whichwill be indicated in the claims.

For a fuller understanding of the nature and objects of the invention,reference should be had to the following detailed description taken inconnection with the accompanying drawing wherein:

Figure 1 is an isometric, diagrammatic view of one preferred form of theinvention during the use thereof, with parts cut away for clarity ofillustration;

Fig. 2 is a diagrammatic, exaggerated, enlarged, sectional view takenalong the line 2-4. of Fig. 1; and

Fig. 3 is a diagrammatic, exa gerated, enlarged, sectional view similarto Fig. 2 wherein the operation of removing the processed positive imageis shown.

In general, the present invention relates to an improved compositeprint-receiving sheet for having transfer prints formed thereon. In onepreferred form the composite sheet comprises a suitable image-carryinglayer on which there is mounted a framing means in the form of a thinpaper mask having an aperture therein for defining an image-receivingarea on the imagecarrying layer. A section of the image-carrying layer,including this image-receiving area, is detachable from the remainder ofthe image-receiv- 55 ing layer and is also strippable from the mask.

The mask serves to confine the image formed on the image-carrying layerto the image-receiving area so that when the detachable section isremoved it provides a finished print in which the image is bounded by adecorative border.

The product of the present invention also preferably includes acontainer releasably holding the processing liquid and a trap fortrapping excess spread liquid, said container and trap being placed ontop of the mask. Thus the liquid, when released from the container andspread, is trapped between the photosensitive layer on the one hand andthe mask and image area of the image-carrying layer on the other hand.

Referring now to Fig. 1,-there is shown an isometric, diagrammatic viewof one preferred form of the invention with portions thereof cut awayfor clarity of illustration. In this figure, Ill represents aphotosensitive layer having its photosensitive surface extendingupwardly. An imagecarrying layer I 2 is shown with a positive image areaIn on its upper surface. This area l2a is defined by a cut-away portionof a mask l4 secured to the surface of the image-carrying layer. Placedon top of the framing mask i4 is a container l6 having therein aprocessing liquid 11. This container extends transversely of theimagecarrying layer and is capable of releasin its contained liquid forspreading across area I M. Adjacent the opposite edge of area 12a is atrap comprising a pair of trapping members l8. Extending longitudinallyof the image-carrying layer a ong the margins thereof is a pair ofspacer strips 20 which, together with marginal portions of the mask l4,predeterminedly separate the photosensitive and image-carrying layers.In a preferred form of the invention, the image-carrying layer I2 isprovided with a plurality of perforations 22 to permit tearing out ofthe image area portion lZa, and a hole 24 may also be provided forassisting in commencing such tearing. As can be seen the hole 24 ispreferably positioned under the container l6 and a correspon ing hole 26is provided in the mask l4, this latter hole being somewhat larger thanhole 24.

Referring now to Fig. 2 which is an exaggerated, diagrammatic, enlargedsectional view of the image-carrying layer of Fig. 1 taken along theline 22, there are shown in more detail certain aspects of the presentinvention. In Fig. 2, like numbers refer to like elements in the otherfigures. As can be seen from an. examination of Fig. 2, there are twolayers 28 and 39 between the mask I 4 and the image-carrying layer I2.Layer 2B is preferably a plastic such as polyvinyl alcohol, while layer30 is preferably a plastic such ethyl cellulose. These two incompatibleplastie layers adhere more strongly to their adjacent paper layers thanthey adhere to each other, although their adherence to each other issufficient to hold the mask smoothly on the surface of theimage-carrying layer during the manufacture, storage and use of theproduct.

In a preferred form of the invention the photosensitive layer Icomprises a paper base upon which is coated a layer ll (shown in Fig. 3)of a silver halide emulsion and preferably a gelatino silver iodobromideemulsion. The imagecarrying layer l2 preferably comprises a sheet ofbaryta paper which has been treated as set forth in the followingnonlimiting example:

Example 1 A sheet of single-weight baryta paper is run through a bathcontaining by weight 11 grams of cadmium acetate, .37 gram of leadacetate end 11 grams of zinc nitrate per 100 cc. of water, the sheetbeing in contact with the bath for about seconds.

Solution A is prepared by adding 60 grams of cadmium acetate, 2 grams oflead acetate and 60 grams of zinc nitrate to'200 cc. of water. SolutionB is prepared by adding 28 grams of sodium sulfide and 300 grams ofsilica aerogel to 2800 cc. of water. Solution C is prepared by adding160 cc. of solution A to 500 cc. of solution B and thoroughly mixing.The resulting mixture is then applied to the surface of the previouslycoated baryta paper by dipping the sheet into a bath of the mix andremoving the excess mix from the sheet, as it leaves the bath, by

means of a soft rubber bufling roll which rotates in a directionopposite to the direction of travel of the sheet. Thereafter the sheetis coated with a 0.5% water solution of gelatin to provide a surface towhich the mask adheres well. Al-

ternatively, the sheet may be coated with a so- Example 2 Layer 28 isapplied by passing the sheet through a water solution of the plastic;such as a 10% water solution of polyvinyl alcohol, and removing theexcess by means of a doctor blade and roller, the resulting coatingbeing thick enough to give a'shiny smoothsurface'tothe mask. Afterdrying the polyvinyl alcohol'coat, layer 30 is similarly applied by useof a solution containing 80 grams of ethyl cell ulose,13' cc. of diethylphthalate', 320 cc. oftoluene and 80 0'0. of denatured alcohol. In apreferredform of the invention, about 3.24 cc'. per square foot ofpolyvinyl alcohol solution andabout 754"00. per'square foot ofethyl"cellulose solution are applied to the tissue paper. The ethyl'cellulosecoating, together with the polyvinyl alcohol coating, increasesthethickness ofthe tissue paper to about .0025 to .003 inch. Otherorganic solvents such, for example, as isopropyl acetate may be used.

The coated tissue paper, after drying, is next cut to the shape shown inFig. 1, the image area portion and the hole 26 being stamped out by asuitable die. Thereafter the mask is bonded to the previously preparedbaryta paper, the ethyl cellulose coating of the mask being next to thebaryta surface. This bonding may be accomplished, for example, bypassing the two sheets between a pair of 4-inch steel rolls under an 18pound load and having surface temperatures of between 250 and 300F. Withsuch temperatures and pressures the paper speed may be about 9 inchesper minute.

In still another method of preparing and adhering the mask, the stepsset forth in the following nonlimiting example are followed:

Example 3 The mask, comprising a .0015 inch thick calendered condensertissue paper is coated in a polyvinyl alcohol bath of the type set forthin Exemple 2. "Then an ethyl cellulose coating is applied from a bathcontaining 500 cc. of isopropyl alcohol, 60 grams of ethyl cellulose and12 grams of triphenyl phosphate. After the mask has been cut to shape,it is secured to the imagecarrying layer by placing the two sheetsbetween platens, the platen adjacent the mask being heated to about 320F. The platens are then squeezed together under a one ton pressure forless than second.

The edge spacer strips 20 are then applied to the mask prepared inaccordance with Example 1 or 2, these spacer strips 20 preferablycomprising kraft paper, or cellophane, about .001 to .0015 inch thickand having a suitable pressuresensitive adhesive such as a blend ofunvulcanized rubber and a tack-producing resin. The strips preferablyraise the total thickness of strips and mask, at the marginal portionsof the image-carrying layer, to about .004 inch. The containers areformed of a paper-backed metal foil having an alkali-inert inner coatingof polyvinyl butyral and a strip of ethyl cellulose along the sealededge as described in the copending application of Edwin H. Land, SerialNo. 652,612, filed March 7, 1946.

The transversely tapered trapping members 18 are preferably made of asemi-crepe paper tape about .15 inch thick secured to the mask by meansof a suitable adhesive.

The container is preferably secured to the image-carrying layer by meansof a strip of an adhesive, for example, polyvinyl butyral, applied tothe bottom of the leading edge thereof. The leadingv edge is thenflattened and sealed to the image-carrying layer by pressing downwardlywith a heated narrow iron, for example.

In one preferred form of the invention, the photosensitive layer I0comprises a suitable paper base upon which is coated a fast gelatinosilver iodobromide photosensitive emulsion. For use with such anemulsion and an imagecarrying layer as prepared in Example 1, apreferred liquid composition includes the following ingredients in therelative proportions given be- Example 4 Grams Water 1860 Sodiumcarboxymethyl cellulose 93 Sodium sulfite '78 Sodium hydroxide 74.6Sodium thiosulfate 14.5 Citric acid 38.5 Hydroquinone 52.0Chlorobenzotriazole 1.5

In the use of the novel product described above, the photosensitiveemulsion I l of the photosensitive layer I0 is suitably exposed in thecamera,

, the two layers Ill-l2 constituting the preferred product of theinvention being suitably disposed within the camera So that they may beadvanced past a processing means in the camera with the exposed area ofthe photosensitive layer in coincident superposed relation to thepositive image area I20. of the image-carrying layer. In a. preferredtype of camera the processing means comprises a pair of pressure rollsindicated at 40 in Fig. 1. As the two layers Ill-l2 pass between theserolls. the container I6 is positioned therebetween and the liquid I! isforced therefrom by the increased hydraulic pressure created by therolls 40. Continued movement of the two layers causes the releasedliouid to be spread in a uniform thin lay r between the two outer layersI0l 2. the thickness of the spread layer of liquid being determined bythe thickness of the s acer strips and mask [4 (including coatings 28and This layer of spread processing liouid I1 is shown in Fig. 3, itbein seen that the thickness of the spread layer of liquid 11 adjacentarea 12a is about eoual to the total thickness of the spacer 20 and thecomposite mask M. Licuid s read beyond the end of area iZa is trappeddue to the separation of the pressure rolls, with conseouent decrease inhydraulic pressure on the liquid. by the trapping members I8. Motion ofthe product is then preferably stopped and the composite lamination ismaintained in the dark for about 1 minute. A door provided in the cameramay then be opened and the positive image area 12a. can be removed fromthe lamination by inserting a fingernail through hole 24 (shown inFig. 1) and tearing the image-carrying layer along perforations 22.Since the mask I4 is cut away at 20 in the neighborhood of hole 24. thestripping of the image-carryin layer from the mask at the same time isfacilitated. As can be seen from Fig. 3,

that portion of the ethyl cellulose layer 30 on tho image area 12a isstripped away from its adjacent polyvinyl alcohol layer 28. The portionof ethyl cellulose 30 adhering to image area lZa thus forms a border forthe positive image formed in or under layer !1 of the processing liquid.It should also be noted that the portions of liquid I! spread betweenthe mask [4 and the photosensitive layer 10 are trapped between theselayers when image area Ila is removed.

It should be pointed out. in connection with the diagrammaticrepresentation of Fig. 3, that the layer of spread liouid quickly driesout, during and after the processing, to form a film of about .0002 inchthick. Thus, when the time occurs for the image area i2a to be torn out,the film ll formed by the spread liquid is considerably thinner thanshown, although it is usually not completely dry within a minute ofspreading. The latter portion of the drying is accomplished byevaporation of the water from the surface thereof exposed as a result ofremoval of area 12a.

When the product, prepared as set forth in ac cordance with Examples 1and 2, is processed by spreading the liquid between the photosensitiveand image-carrying layers, the developer develops exposed silver halidegrains and the sodium thiosulfate, concurrently with the development,forms soluble silver complexes with unexposed silver halide grains.These complexes migrate to the image-carrying layer where they areconverted to a positive image comprising silver, the sulfide slowlyreleased from the surface of the image-carrying layer forming silversulfide specks around which large silver grains are formed. The cadmiumacetate and zinc nitrate are slowly released to lower the alkalinity ofthe liquid toa point where oxidation of the excess developer does notoccur. Meanwhile, the sodium carboxymethyl cellulose is forming adimensionally stable film which adheres to the surface of theimagecarrying layer. The above-described reactions (with the exceptionof the lowering of the pH) are completed in about 1 minute and thepositive image area is then separated from the lamina tion comprisingthe photosensitive and imagecarrying layers. As explained above, thissepa* ration is preferably accomplished by opening the door, inserting afingernail through hole 24 and tearing the image-carrying layer alonglines 22, thus revealing the final stable positive image.

While in the preceding examples the mask M has been shown as strippablysecured to the image-carrying layer [2 by the use of two layers ofincompatible plastics which provide a strippable bend, it will beappreciated that other bonding means or structures may be employed. Forexample, the mask may be coated on one surface with a layer of a singlematerial possessing adhesive properties and having a greater affinityfor the material of the mask than for the material of the receivingsheet. In this regard, a water-soap solution may be utilized, forexample a 5 to 40% water-soap solution made of Ivory soap.Alternatively, the mask may be coated with a thin layer of a fattysubstance or soap which is insoluble in water and then may be coveredafter drying with a layer of hardened gelatin or collodion. In regard tosoap, or soap and hardened gelatin, reference is made to Photography,Theory and Practice by L. P. Clerc, second edi tion, Pitman PublishingCorp, New York, New York, page 159, footnote 3, and also to thecopending application of Edwin H. Land, Serial No. 708,007, filedNovember 6, 1946, for Photographic Product and Process (now Patent No.2,647,055, issued July 28, 1953) and Patent No. 2,563,342, issued toEdwin H. Land on August 7, 1951, for Photographic Product and Process.Additionally, the mask surface to be adhered to the imagecarrying layermay be coated with gelatin to which has been added an appropriate amountof glycerin whereby to suitably control the bond strength of thegelatin, as is well understood by the art. In lieu of these practices,the mask may be coated with a suitable pressure-bondable rubber cement.These and other procedures for forming a strippable bond between themask and the image-carrying layer are employable in carrying out theinvention. A mask coated with any. of the just-described strippinglayers is intended to be adhered to the image-carrying layer in themanner described in Example 2 hereof by passing the finished mask andthe receiving sheet layer between pressure rolls.

While preferred forms of the invention have been described above,numerous other modifications thereof are possible without departing fromthe scope thereof. For example, the mask l4 (plus layers 28 and 30) maybe made thicker than the .0025 to .003 inch mentioned above. In thiscase, the spacing strips may be eliminated since the mask will givesufiicient thickness to allow for proper spread of the liquid.

With either of the above modifications of the invention, the top surfaceof the mask (and the spacing strip 20) may be coated with a Watersolubleadhesive to increase the adhesion of the mask to the emulsion layer l I.Such an adhesive may comprise gum arabic coated from a water solutionthereof onto that side of the mask opposite to coatings 28 and 30.

In addition to the above modifications, the containers and traps of thepresent invention may be secured to the photosensitive rather than theimage-carrying layer. Also, the spacing strips may be eliminated inseveral other preferred forms of the invention. In one of these forms,the mask thickness (including layers 28 and 30) is about the thicknessdesired for the layer of spread liquid. In another preferred form, themask thickness is as described previously and one of the pressure rollsof the camera has thickened shoulder portions engaging the margins ofthe lamination formed by the pressure rolls. Such shoulders may have a,radius greater, by about .001 to .002 inch, than the other part of theroll, depending upon the thickness of the mask and the desired thicknessof spread liquid. Equally, numerous other processing liquids may beemployed with numerous types of photosensitive materials andimage-carrying layers of the type described, for example, in thecopending application of Edwin H. Land, Serial No. 729,578, filedFebruary 19, 1947.

When a slow silver bromide or silver chloride emulsion is used, theimage-carrying layer I! may comprise a sheet of plain baryta paper towhich the mask of Example 2 or 3 is laminated as described therein. Withsuch a photosensitive layer and image-carrying layer, the liquid ofExample 4 may be used, preferably without the chlorobenzotriazole.

The liquid in the container may carry only a part of the processingreagents and others may be included in solid form in the sheets. Forexample, the developer may be included in the photosensitive emulsion.

Since certain changes may be made in the above product without departingfrom the scope of the invention herein involved, it is intended that allmatter contained in the above description or shown in the accompanyingdrawing shall be interpreted as illustrative and not in a limitingsense.

What is claimed is:

1. As a new product, a composite print-receiving sheet comprising, incombination, an imagereceiving layer, a masking layer superposed on andsecured to said image-receiving layer and having an aperture thereinwhich leaves an area of said image-receiving layer uncovered forreceiving an image by transfer, said image-receiving layer beingstrippable from said masking layer and being provided with perforationswhich extend at least partially therethrough and which are located insurrounding relation to said uncovered area at positions outside of themarginal edges of said uncovered area whereby to provide a detachablesection which includes the uncovered area and a border surrounding saidarea, said masking layer overlying said perforations to cover the same,and a rupturable container mounted on said masking layer adjacent oneedge of said uncovered area, said container carrying a processing liquidwhich is spreadable from said container over said uncovered area, theliquid in the container being suflicient in amount to cover saiduncovered area, said sheet containing photographic reagents, including asilver halide developer, so located that the release of the liquid fromthe container over the uncovered area of the image-receiving layerplaces said reagents in condition to form a transfer print of a latentimage contained in a silver halide emulsion superposed on said uncoveredarea.

2. As a new product, a composite print-receiving sheet comprising, incombination, an imagereceiving layer, a masking layer superposed on andsecured to said image-receiving layer and having an aperture thereinwhich leaves an area of said image-receiving layer uncovered forreceiving an image by transfer, said image-receiving layer beingstrippable from said masking layer and being provided with perforationwhich extend at least partially therethrough and which are located insurrounding relation to said uncovered area at positions outside of themargina1 edges of said uncovered area whereby to provide a detachablesection which includes the uncovered area and a border surrounding saidarea, said image-receiving layer having an aperture adjacent theperforations to facilitate manual detachment of said detachable sectionalong the perforations, said masking layer overlying said perforationsto cover the same, and a rupturable container mounted on said maskinglayer adjacent one edge of said uncovered area, said container carryinga processing liquid which is spreadable from said container over saiduncovered area, the liquid in the container being suflicient in amountto cover said uncovered area, said sheet containing photographicreagents, including a silver halide developer, so located that therelease of the liquid from the container over the uncovered area of theimage-receiving layer places said reagents in condition to form atransfer print of a latent image contained in a silver halide emulsionsuperposed on said uncovered area.

3. As a. new product, a composite print-receiving sheet comprising, incombination, an imagereceiving layer, a masking layer superposed on andsecured to said image-receiving layer and having an aperture thereinwhich leaves an area of said image-receiving layer uncovered forreceiving an image by transfer, said image-receiving layer beingstrippable from said masking layer and being provided with perforationswhich extend at least partially therethrough and which are located insurrounding relation to said uncovered area at positions outside of themarginal edges of said uncovered area whereby to provide a detachablesection which includes the uncovered area and a border surrounding saidarea, said masking layer overlyin said perforations to cover the same,and a rupturable container mounted on said masking layer adiacent oneedge of said uncovered area, said container carrying a processing liquidwhich is spreadable from said container over said uncovered area, andtrapping means mounted on the masking layer adjacent the edge of saiduncovered area opposite the container, said trapping means being adaptedto confine liquid from the container which spreads beyond said uncoveredarea, the liquid in the container being suflicient in amount to coversaid uncovered area, said sheet containing photographic reagents,including a silver halide developer, so located that the release of theliquid from the container over the uncovered area of the image-receivinglayer places said reagents in condition to form a transfer print of alatent image contained in a silver halide emulsion superposed on saiduncovered area.

4. The product of claim 1 wherein the reagents include a silver halidesolvent in addition to the silver halide developer.

5. The product of claim 4 wherein the silver halide developer and thesilver halide solvent are contained in solution in the liquid in thecontainer.

6. A photographic product comprising an elongated, fiexible, compositeimage-receiving sheet material for use in a photographic transferprocess as image-receptive material for receiving a transfer image andcomprising an image-receiving layer, a masking layer superposed on andsecured to a surface of said image-receiving layer and providing a maskover portions of said image-receiving layer, said masking layer havingat least one aperture therein which defines a picture area by leaving anarea on said imagereceiving layer uncovered for receiving an image bytransfer, said image-receiving layer being strippable from said maskinglayer and being provided with perforations which extend at leastpartially therethrough and which are located in adjacent relation toeach said uncovered area, at 20 positions outside of marginal edges ofsaid uncovered area whereby to provide a detachable section whichincludes said uncovered area and a border surrounding the area, saidmasking layer overlying said perforations to cover the same, and arupturable container mounted on said masking layer adjacent one edge ofeach said uncovered area, said container carrying a processing liquidwhich is spreadable from said container over said uncovered area, theliquid in the container being sufiicient in amount to cover saiduncovered area, said product containing photographic reagents, includinga silver halide developer, so located that the release of the liquidfrom the container over an uncovered area of the image-receiving layerplaces said reagents in condition to form a transfer print of a latentimage contained in a silver halide emulsion superposed on said uncoveredarea.

WILLIAM J. MCCUNE, JR.

No references cited.

